Small particle size material has a large surface to volume ratio. For this reason, chemical processes often work better by using small size particles for feed stock material. Small particle size is also important for pharmaceuticals and nutritional supplements, which are taken up by the body more easily and effectively when in small particle sizes.
One such material with many industrial uses is carbon black, which is an amorphous form of pure carbon. Carbon black is useful as a carbon feed stock for chemical processes, e.g. in plastic production, in compounding of rubber, and in the production of inks and pigments. Typically, carbon black is produced by burning acetylene and other organic fuels under low oxygen conditions. This is energy intensive and creates gas by-products that are undesirable.
There is a growing interest in recovery of carbon from scrap material so it can be recycled in useful ways. One such source of carbon is from pyrolyzed scrap vehicle tires. Millions of kilograms of char (essentially pure carbon) are potentially available from tire “waste.” Chars having different properties and characteristics can be made consistently by changing process parameters, such as pyrolysis temperature, heating rate, pyrolysis time, the rotating speed of the reactor, and the presence or absence of additives.
Such pyrolytic char particles typically range in size from about one micron to over one millimeter. Carbon particles of this size range are too large for use in compounding of tire tread rubber, plastics and other materials or for use as pigment in printers. The char must therefore be made into particle sizes of about one micron or less in order to generate carbon that can be used to produce new products. For most large volume uses, such fine particle sizes are desirable or required. Since thousands of tons of fine carbon particles are used in various industries, machines that can process large amounts of material are required.
Other hard materials that are crystalline or amorphous in form are generally difficult to grind into smaller particle sizes that would be useful for uses such as food processing or nutritional supplements. Such materials include crystals of organic molecules containing minerals and non-mineral containing organic compounds. For most of these materials a particle size of less than about 50 microns is highly desirable.